Heat exchange apparatus



June 27, 1933. M u sc 1,915,742

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Patented June 27, 1933 UNITED STATES PATENT OFFICE ROBERT MAUTSCH, or BRSSELS, BELGIUM, AssIGNon .ro MANUFAcrUnE GENEBALE METALLURGIQUE,soorr'i'rn ANONYME, or BRUSSELS, BELGIUM, A COMPANY on BELGIUM HEATEXCHANGE ArrARArUs Application filed November 25, 1931, Serial No.577,329, and in Belgium November 28, 1930.

' The present invention relates to apparatuses such as radiators,evaporators or the like, the heat exchange surfaces whereof areconstituted by corrugated or puckered fins,

threaded upon substantially parallel tubes to interconnect two or moretubes appertainingto one same unit of the apparatus. When said fins arethreaded upon said tubes and are thereafter shrunk thereto by expansionof the tube, it frequently occurs that the stress of said expansionslightly flexes said tubes or otherwise forces them out of parallelism,whereby the appearance -of the apparatus is impaired and difficultiesmay arise when the members are assembled. Furthermore, when constructingapparatuses whose corrugated fins must contact with each other toconstitute a honeycomb pattern, great care is required in order toensure that the apicesof the corrugations of adjacent fins face eachother accurately, since otherwise said fins intermesh instead ofremaining spaced apart and the desired object is not attained. Care alsoshould be taken to avoid hindering the freedom of circulation of thefluid ing the tubes.

According to my invention, these difficuh ties are very simply obviatedby the interposition of' flat fins between said corrugated fins, and theuse of corrugated fins comprising groups of larger corrugations and ofsmaller corrugations preferably arranged in alternating relation.Said'flat fins constitute rigid stays between the tubular members andhold the latter securely and accurately parallel with each other whensaid corrugated and fiat pins are shrunk thereon and said corrugatedfins, being separated from each other by said flat fins, cannotintermesh even though their apices may notcoincide, a function which-thecorrugated fins alone cannot fulfil, since they are easily extended andcontracted transversely of their corrugations.

This invention "therefore allows the corrugated fins to be formed withless accuracy than has-been required hitherto and obviates the necessityof scrapping those of-said corrugated fins which are not exactly togauge, since the fiat fins automatically ensure the surrounduniformspacing of the corrugated fins between which they are interposed. Forthe same reason it is no longer necessary, in order to form a honeycombpattern, that the apices of the corrugations of the fins should registeraccurately with each other, a' novel arrangement becoming possible, onthe contrary, if the apices of the corrugations of one fin are placedopposite the hollows in the corrugations of the fin adjacent thereto,the fiat fin interposed therebetween preventing the intermeshing of theapices oiione corrugated fin with the hollows in the other fin.

My invention is applicable to all forms of heat exchange apparatusmembers having corrugated fins threaded upon tubes, whatever may be thearrangement and shape of the corrugations or creases thereof, or therelative dimensions of said corrugations and of the tubes passingthrough said fins. It

is likewise immaterial whether the fins are spaced apart from or incontact with each other, orjwhether they all contact with each other oronly contact in groups. Furthermore, flat fins may be caused toalternate regularly with corrugated fins, or'be merely interspersedbetween the latter as desired.

The attached drawing illustrates by way of example some portions of heatexchange members having corrugated fins and flat interposed fins,according to this invention. In

said drawing:

Fig. 1 is a plan view of an arrangement wherein the corrugated fins arespaced apart from the flat fins,

Fig. 2 illustrates a similar member where.

of the corrugated fins and the fiat fins are contact, and v Fig. 3 showsa modification to the arrangement of Fig. 2.

Each 'of the heat exchange apparatus members illustrated in the drawingcomprises two parallel tubes a wherein. for example, the refrigeratingor the heating fluid is caused to flow, and corrugated fins b and flatfins a, threaded upon said tubes to constitute the contact area for theother fluid flowing therebetween. Fins b have groups of largecorrugations m alternating'with groups of smaller corrugations n. Due tothe considerable extension provided by their corrugations, fins 6 afforda large contact area whilst the flat fins 0, which alternate with saidcorrugated fins 6, act as rigid. stays for the tubes a, while afi'ordingheat exchange areas likewise.

Fins b and c (Fig. 1) may bespaced apart as desired, said spa e beingadjusted by insorting between said fins suitable distance pieces, whichare withdrawn after the fins have been shrunk upon the tubes.

In Fig. 2, the fins are in contact with each other to form a structuresomewhat resembling a honeycomb, the corrugated fins b being so arrangedthat the apices of the corrugations of adjacent fins faceeach other.Said apices bear against the flat fin c interposed between two adjacentcorrugated fins, and the spaces between the latter cannot thereforebecome irregular, even though their apices should be slightly offsetwhereas some intermeshing of said offset corrugated fins would beunavoidable if no flat fin were inserted therebetween. The small corruations n are preferably provided where the us are intersected by thetubes a, in order to leave a free space for the circulation of thesurrounding fluid on all sides of the tubes.

An example is illustrated in Fig. 3 wherein such offsetting isintentional and is carried to the point that the apices of one fin 6face the depressions in the adjacent fin b, whereby a novel honeycombarrangement is obtained.

I claim:

1. In a heat exchange ap aratus, substantially parallel tubular mem ers,fins having alternating grou s' of large and small corrugations formetherein, and fiat fins, said corrugated fins and fiat fins beingthreaded and shrunk upon said tubular members substantially at rightangles to the same, and said flat fins being interposed between saidcorrugated fins said small corrugations being spaced away from said flatfins.

2. In a heat exchange apparatus, the combination of substantiallyparallel tubular members, corrugated fins and flat rigid fins threadedand shrunk upon said tubular members at substantially right anglesthereto, said rigid flat fins being in alternate relationship with saidcorrugated fins and constituting rigid stays between said tubularmembers said corrugated fins having alternating groups of larger andsmaller corrugations, said tubular members extending through saidsmaller corrugations, the apices of said larger corrugations contactingwith said flat fins, and the apices of said smaller corrugations beingspaced away from said flat fins.

'3. In a honeycomb heat exchange apparatus, the combination ofsubstantially parallel tubular members, and corrugated fins and rigidflat fins threaded and shrunk upon said tubular members at substantiallyright angles thereto, said rigid flat fins valternating with saidcorrugated fins, and said corrugated fins and rigid flat fins bearingagainst and supportingeach other in a uniform honeycomb formationbetween said tubes and being spaced apart from each other in proximityto said tubes.

In testimony whereof I have signed my' name to this specification.

ROBERT UTSCH.

